Normally, large mammals live longer that small ones. The common example is that elephants can live up to 70 years, whereas mice live only 4. Dogs, however, seem to defy the norm - having a larger body is costly in terms of longevity. New research by Dr. Daniel Promislow, a Canadian Professor of Genetics at the University of Georgia in Athens, has determined that big dogs age at a faster rate and are more prone to typical age-related illness earlier on than small breeds. He and his colleagues propose that cancer is more common in large dogs, as a consequence of humans breeding dogs for size over the last 150 year or so. The same mechanism that has helped protect cells from cancer in large mammals, like elephants and whales over millions of years, has not yet evolved in large dogs.
When an asteroid struck the Yucatan peninsula, 66 million years ago, it triggered the extinction of the dinosaurs and many other species. But it wasn't just the impact alone that devastated ecosystems - it was the after-effects. One of the big contributors, according to Dr. Doug Robertson, Emeritus Fellow at the Cooperative Institute for Research in Environmental Sciences at the University of Colorado in Boulder, was the global firestorm created by the re-entry of the huge amount of material that the asteroid's impact ejected into space. The re-entering material would have heated the upper atmosphere to about 1200 degrees C, turning the entire planet to "broil."
Paper in the Journal of Geophysical Research, Biogeosciences
Giraffes' feet are a very long way from their brains, and this presents certain problems to the animal. One in particular is that nerve signals - like the sensation of uncertain footing, for example - have a long way to travel to get from foot to brain. Heather More, a PhD student in the Department of Biomedical Physiology and Kinesiology at Simon Fraser University, studied the speed of nerve conduction in giraffes in South Africa. She calculated that it must take a significant fraction of a second for a signal to get from foot to brain and back again, meaning that giraffes are challenged by considerable risks of tripping, which would be very dangerous for such a large animal.
Using a new seismic imaging technology, geologists have determined that the rocks that make up the mountains of western North America were actually formed in the Pacific, and then transported 1000 km to the West Coast. Mitch Mihalynuk, Senior Project Geologist with the Geological Survey of British Columbia in Victoria, and colleagues, used "earthquake tomography," which essentially allows them to do a deep 3-D scan of the Earth's crust and mantle. This revealed a new history of tectonic plate collisions in the Pacific that led to the mountain-building of western North America. Related Links
Dr. Miguel Nicolelis is a pioneer in the field of brain-machine interfaces, which could make it possible to control computers and other devices with just a thought. In his experiments, he's used arrays of electrodes implanted into the brains of experimental animals to read the electrical activity of the brain's neurons. This activity is then interpreted by computer models, and used to control robotic limbs, or virtual-reality avatars. In his most recent work, he's even been able to provide feedback into the sensory parts of the brain, giving these devices a sense of touch. This technology could be incredibly valuable for people with disabilities and could even be used to extend human abilities beyond the capacities of our own bodies. Related Links
CBC's Rewind takes a look at space travel predictions since 1946. Listen to great clips from the CBC Radio Archives, with new commentary from Bob McDonald, about where space exploration should have taken us by now.